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BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321
Read of size 1 at addr ffff88809d9c6d4a by task syz-executor.3/11954

CPU: 1 PID: 11954 Comm: syz-executor.3 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321
 sscanf+0x6c/0x90 lib/vsprintf.c:3527
 smk_set_cipso+0x374/0x6c0 security/smack/smackfs.c:908
 __vfs_write+0x9c/0x6e0 fs/read_write.c:495
 __kernel_write+0x120/0x350 fs/read_write.c:516
 write_pipe_buf+0xf9/0x150 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x351/0x8b0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x1eb/0x2a0 fs/splice.c:1016
 splice_direct_to_actor+0x4a2/0xb60 fs/splice.c:971
 do_splice_direct+0x201/0x340 fs/splice.c:1059
 do_sendfile+0x809/0xfe0 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1568
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007f26ad17dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00000000004fd720 RCX: 000000000045cb29
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000902 R14: 00000000004cbe0a R15: 00007f26ad17e6d4

Allocated by task 11954:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc_track_caller+0x249/0x320 mm/slab.c:3671
 memdup_user_nul+0x26/0xf0 mm/util.c:259
 smk_set_cipso+0xff/0x6c0 security/smack/smackfs.c:859
 __vfs_write+0x9c/0x6e0 fs/read_write.c:495
 __kernel_write+0x120/0x350 fs/read_write.c:516
 write_pipe_buf+0xf9/0x150 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x351/0x8b0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x1eb/0x2a0 fs/splice.c:1016
 splice_direct_to_actor+0x4a2/0xb60 fs/splice.c:971
 do_splice_direct+0x201/0x340 fs/splice.c:1059
 do_sendfile+0x809/0xfe0 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1568
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 7034:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 translate_table+0x1085/0x20e0 net/ipv4/netfilter/ip_tables.c:712
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x28b/0x4c0 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x2be/0x2e0 net/netfilter/nf_sockopt.c:115
 __sys_setsockopt+0x564/0x710 net/socket.c:2127
 __do_sys_setsockopt net/socket.c:2143 [inline]
 __se_sys_setsockopt net/socket.c:2140 [inline]
 __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2140
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809d9c6d40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 10 bytes inside of
 32-byte region [ffff88809d9c6d40, ffff88809d9c6d60)
The buggy address belongs to the page:
page:ffffea0002767180 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809d9c6fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027af288 ffffea0002a53508 ffff8880aa4001c0
raw: ffff88809d9c6fc1 ffff88809d9c6000 0000000100000032 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809d9c6c00: fb fb fb fb fc fc fc fc 06 fc fc fc fc fc fc fc
 ffff88809d9c6c80: 06 fc fc fc fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff88809d9c6d00: 00 00 fc fc fc fc fc fc 00 fc fc fc fc fc fc fc
                                              ^
 ffff88809d9c6d80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809d9c6e00: 00 00 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
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